Field of the Invention
The present invention relates to a liquid ejection apparatus for ejecting liquid through an ejection opening to perform printing and a liquid ejection head and a printing element substrate used for the liquid ejection apparatus.
Description of the Related Art
Liquid ejection apparatuses include, for example, a liquid ejection apparatus in which a liquid ejection head can be used to use thermal energy from a heating resistor element to eject liquid through ejection openings provided in a printing element substrate. In order to allow this type of liquid ejection apparatus to obtain a favorable image, for the purpose of minimizing a density variation or an uneven density of a printed image for example, various controls have been performed to stabilize the ejection amount ejected through liquid ejection heads.
A higher liquid temperature causes a lower liquid viscosity and thus liquid can be ejected more easily, thereby providing a higher ejection amount. Thus, a liquid ejection apparatus controls a liquid viscosity having an influence on the ejection amount for example by adjusting the liquid temperature (hereinafter also may be referred to as “temperature adjustment”). In the case of such a liquid ejection head, the temperature of the printing element substrate highly has an influence on the liquid temperature. In the case of a liquid ejection head in which a printing element substrate including a plurality of heating resistor elements is provided in a support body having a high thermal conductivity, the heat from the printing element substrate is diffused to the support body.
Thus, the temperature of the entire printing element substrate can be predicted by providing temperature sensors at an end and the center of the printing element substrate. Japanese Patent Laid-Open No. 2009-262510 discloses a method of providing, in order to accurately measure a rapid temperature change of a flow path connected to an ejection opening in particular in the vicinity of a liquid ejection head, temperature sensors are provided at an end and a plurality of positions of the center of the flow path connected to the ejection opening.
However, in the case of the method disclosed in Japanese Patent Laid-Open No. 2009-262510, although a temperature change of the printing element can be known, the temperature change cannot be reflected on the control of the respective ejection openings. Therefore, not only the temperature detection at an end and the center but also a more detailed temperature detection are required. Thus, a temperature sensor can be provided in the vicinity of the ejection opening to thereby provide a more detailed temperature detection and a heater can be driven-controlled in accordance with the temperature in the vicinity of an ejection opening to thereby provide a higher printing quality. Japanese Patent Laid-Open No. 2010-120301 discloses a method of detecting an ejection failure by an independent temperature detection unit to individually detect the temperatures of the respective ejection openings.
However, temperature sensors are provided in the vicinity of if all ejection openings, such wirings are required that are used to cause constant current corresponding to the number of the sensors to flow and a voltage is outputted, thus undesirably resulting in a printing element substrate having a larger size. Furthermore, in order to provide a feedback to a control for an individual detection and a printing control based on an individually-detected temperature, a higher data amount is required, thus causing a slower printing speed.